I am well aware of what the term explosive means, but I see an explosive movement as a move than cannot be performed slowly such as cleans/snatches, other moves can be made explosive like in your example but they can be done slowly as well. I guess it's just a difference of opinion on explosive movements vs exploding during a move. If that makes sense. As for the cage/rack, I use it almost daily and I am very familiar with bands and chains and the hook system.

Yev, I've thought of doing it that way as well but I didn't want the medium weight week to affect heavy singles week.

Either way it's a solid set up, I think it's a great way to periodize your training. Gives the body a break without getting into the 12-16 week block periodization systems where you are planning so far ahead not necessarily knowing how your body will respond from week 1 to week 12.

Fast explosive movements on the positive part of rep with slower returns build fast twich muscle fiber that are the fibers that have the most number in the muscle so stimulating those fibers adds more size. Slower returns help avoid injuries as opposed to dropping the weight as fast as lifting it on the positive part and builds slow twich fibers.So i'm not surprised about your gain on this type of lifting especially if you haven't been doing it before.If training in this mode you should stop the set as soon the reps start to slow down or use a spotter to keep the speed steady trough the set.